FIGURE 6.

Diminished secretion of IFN-γ in T cells with a cleaved form of the CD4 (CD4^low) molecule. A, CD4^high and CD4^low T cells were isolated from the PLNs of BDC2.5 TCR transgenic NOD mice by sorting cells that positively stained with FITC-conjugated anti-Vβ4 TCR chain mAb (1:500) and PE-conjugated anti-CD4 mAb (1:800). The cells were then stimulated with different concentrations of the BDC2.5 mimotope in the presence of antigen-presenting cells (left panel) or phorbol esters (phorbol 12-myristate 13-acetate (PMA)) and ionomycin (right panel). At 48 h after initiation of stimulation, the cells were counted, and culture supernatants were examined by ELISA for IFN-γ concentration. The average of three independent experiments described is shown. B, after stimulation for 72 h with the BDC2.5 mimotope-pulsed antigen-presenting cells, the cells were rested for 48 h and then restimulated with phorbol 12-myristate 13-acetate (10 ng/ml) and ionomycin (1 μm). The GolgiStop reagent was added during the last 8 h of secondary culture. The cytokine production was examined by intracellular staining of cells with allophycocyanin-conjugated mAb against IFN-γ (1:100). The data are representative of three independent experiments. The error bars indicate S.D.